7fl 467 
.S86 
Copy 1 



Prevention 




By 

L. M. Stern 




LitfMARYof CONGRtSS 


Iwu Cooies Hecelved 


OCT 98 190^ 


Copynght Entry 
CLASS A XXc, No. 


OOPY 3. 



CopyriKlitcil, IIKIT 
By L.M. STERN, 

CU'Vi'laiKl, nliiu. 



^ 



RUST 
PREVENTION 



A TREATISE 

On the preservation of Structural Steel 
used in bridges, buildings, fire escapes, 
etc., and Sheet Steel used in buildings, 
metal siding, roofing, smokestacks, 
boiler fronts, and standpipes, etc. 

FOR 

Anyone having in charge their mainte- 
nance. Also property owners, architects 
engineers and metal workers, etc. 

By L. M. STERN 



INTRODUCTION. 

The use of steel has Increased so rapidly within the 
past ten years that the keen eonipetition In cost of pro- 
duction between the manufacturers thereof, has caused 
an enormous amount of this metal (particularly in Sheet 
Steel and Terne Plates for exterior ime) to be thrown 
upon the mnrl<et. of a quality unsatisfactory to those who 
have to slioulder the responsil)ility of its proper main- 
tenance. 

Since tlio advent of tlic Hcssenicr process t>f nuilxinK 
steel cheaply, the use of " charcoal iron " has compara- 
tively decreased. Iron ore is very rarely reduced to pure 
metallic iron for commercial purposes, consequently the 
foreign substances which have not become eliminated 
from it constitutes part of the material entering into its 
transformation into steel. 

The progress of disintein'.ition of steel exi>osed to re- 
actionary agencies largely depends ui>on the quality of 
the metal, nickel steel, for example, being but very 
slightly susceptible to corrosive action, while Bessemer 
process steel being the reverse. 

The intention of this treatise is to deal briefly with 
tlie protection of the surface of the metal, so that cor- 
rosive action may be prevented from exterior sources, and 
in pursuing this course, we must of necessity carrj^ on 
the discussion with the understanding that the steel or 
iron exposed to corrosion is of the quality which ordinar- 
ily comes from the niiil. leaving the question of placing 
(heap and better steel ui)t>ii the market for structural 
purposes to those who manufacture it. 

There are a great many paint manufacturing tx>n- 
cerns w^ho make ridiculous and absurd statements in 
tlu'ir advertising matter, in the claims which they make 

4 



regarding wonderful properties possessed by a material 
which they offer for sale to prevent corrosion and rust 
on all kinds of metal work. 

One large concern advertise that they are the sole 
manufacturers who own a mine yielding graphite of 
such a peculiar flake form that paint made with it pos- 
sesses the wonderful properties of the flakes arranging 
themselves like the shingles on a roof or the scales on a 
fish, during the progress of paintin;g a surface with it, 
claiming as a result thereof, that " the flakes so arranged 
would protect the oil in the interstices from evaporation 
or excessive oxidation." This manufacturer fails to state 
what form these scales would take if the painter would 
forget himself and use his brush in the usual manner, 
plying it back and forth on the surface so that the paint 
would draw from both sides of the brush. 

The property owner should post himself sufficiently 
to be able to guard against deception and fraud. The 
painter cannot be depended upon for any definite knowl- 
edge of metal preservation. He either finds it unprofit- 
able to waste his time thinking about the matter, or has 
no inclination to have his paint cost him more than what 
is absolutely necessary — hence his recommendations and 
advice are more often given than asked for. 

Since the author's first treatise on this subject, pub- 
lished in 1901, extensive practical tests of various pig- 
ments and liquids for their protective durability have 
been under his close surveillance in various sections of 
the country, covering a wide range of climates. More 
truths have been revealed regarding the most suitable 
protective coating to resist the particular climate or 
exiK>sure at hand, and it is to be hoped -that this treatise 
will contribute enough light on this subject to induce 
the architect, engineer or property owner (either having 
charge of construction work or the maintenance of the 
work after completion) to be more cautious in the selec- 
tion of the most suitable materials. 

5 



The author desires it to be luime in iiiliul that as his 
livelihf>o<l depends upon the sale of all kinds of materials 
for the prevention of rust, any influence or aasistance 
that the reader can extend toward their purchase from 
him, will be duly appreciateil, and that the same 
judgment, resolution and practical experience which 
l>rompted the issuance of this treatise will be devoted to 
the interest of those so inclined. 

Theories and the chemistry of paints will herein, as 
far as jiractical, be avoided, and a strict adherence to 
practical l<nowledge maintained as faithfully as poeslble, 
so that the ordinary person, whether experienced or 
otherwise, requiring some good general pointers on the 
subject may find this treatise of some practical and 
financial benefit. 

Very truly yours, 

L. M. Stern, 

571 East Ninkty-ninth street. Ci^vTJ.AyD, Ohio. 



RUST PREVENTION. 



Chapter I. 

Iron Rust and Its Formation. 

Circumstantial evidence convinces us that iron at one 
time, say thousands of years ago, might easily have been 
or in fact was distributed over portions of the earth in 
a metallic state and that the subsequent action of 
oxygen, sulphur, silica and other elements have con- 
verted it into the state in which it is now found and 
which is commonly called iron ore. 

Iron ore resembles rust in appearance and not only 
contains the two important elements of rust, of which it 
principally consists, namely (FezOg), but it contains 
other elements as well, such as sulphur, and silica, &c. ; 
hence it remains for man to undo what nature's labora- 
tory has done for centuries and separate the elements 
closely united in the composition of the ore and thus ob- 
tain the metallic iron for use in the arts. 

Rust is a reddish brown deposit, generally noticed on 
the surface of steel and iron after having undergone de- 
terioration by chemical change, due to exposure to agen- 
cies, causing its formation. It ordinarily consists mostly 
of oxide of iron, together with other minor substances 
and water. 

The compound known as oxide of iron consists of the 
chemical combination of two parts of iron with three 
parts of oxygen, commonly expressed in chemistry by the 
symbol (FeoOg) the first two letters representing the 
Latin term Ferris, meaning iron and the letter O repre- 
senting the word oxygen. 

For the reason that iron oxide is an hydroscopic salt, 
it has the property of absorbing water, intimately holding 
a portion of it in close affinity with its molecules : this, 
however, does not change its chemical composition to any 
appreciable extent, for the reason that the water does 
not form a chemical solution with the oxide. Thus, rust 
is termed a hydrated oxide of iron, which is symbolized 
in chemistry as FejOg + (H^O), which is oxide of iron 



plus water. This water Is free to act on metallic Iron 
into which It may come In contact, forming additional 
rust, thus creaUnt' more room for water absorption and 
continuing Uie process of rust formation Indefinitely. 

The chemical dcH.-oraiX)sltiou of the steel or iron by 
the combination of particles of the metal with oxygen Js 
accelerated by frequent contact of the metal with oxygen 
in a condensed form, such as is found in liquids, and Ite 
subsequent evaiK)ration in the presence of gaseous oxygen 
such as atmospheric oxygen, &c. 

Thus a solution of oxygen in the form of rain, dew 
or other forms of moisture, when deposited on an iron 
surface and quickly evaporated, will rust the surface 
much more readily than if the water or moisture were 
maintained on the surface. In high and dry climates, 
where the proportion of pure oxygen is greater in the 
atmosphere, iron and steel will not rust as quickly as In 
low damp valleys, where fogs and heavy dews are preva- 
lent, so that the conjoint action of atmospheric oxygen 
and water or other forms of moisture may act upon the 
surface. 

A piece of steel can be seen to rust in a few moments 
time after the evaporation of water from the surface. 
All forms of iron, whether sheet iron, steel, pig iron, cast 
iron, malleable iron, or any condition of bare and un- 
protected iron or steel surface exposed to frequent re- 
newals of moisture and atmospheric oxygen, become 
rusted, and the aggressiveness taken by this form of re- 
agent depends not only on the frequency of evaporation 
and renewal of moisture, but on the cleanliness of the 
surface thus exposed and temperature of and active quali- 
ties of the water, coacting with the atmospheric oxygen 
as well, together with the chemical composition of the 
steel, some grades of steel being attacked far more read- 
ily than others. 

The writer has seen steel girders on bridges so badly 
rusted that portions of them, when coming in contact 
with the pressure of the hand, would slough away like 
a rotten log. Some rusted sections would be directly be- 
low the coating of paint, which would be in an almost 
perfect condition on the surface. This rusted metal would 
be piled up in layers, one upon the other, completely af- 
fected through the entire thickness of the original beam, 
which upon examination would reveal the fact that the 
steel had been Imperfectly rolled or refined during the 

8 



process of manufacture, resulting in seams resembling an 
imperfect weld, whicli would accumulate rust and by the 
admission of moisture in the interstices and the contrac- 
tion and expansion of the metal would loosen up the 
crevices between the layers so that they could be rent 
asunder with a pocket knife, like sheets of mica. 

Steel kept under water, in the ground or set in cement, 
which will admit oxygen and moisture and allow the 
same to be evaporated, is eventually doomed to prema- 
ture rust and decay. 

All of the hydroscopic salts, especially common salt, 
magnesium chloride, potassium chloride, ammonium 
chloride aid and assist in forming rust. 

Carbonic dioxide gas (CO2) which is constantly being 
poured into the air from our chimneys and our lungs, 
sulphuretted hydrogen from coke ovens and furnaces, 
likewise attack the metal surface and assist in the for- 
mation of the compound which we call rust. 

Water impregnated with caustic alkali will not rust 
steel readily, provided the steel be immersed in a bath of 
the same and be continually kept beneath the surface. 

Almost all of the acids, when diluted with consider- 
able water, rust iron and steel considerably, and strange 
as it may seem the fact nevertheless remains, that a 
great many acids attack steel more vigorously when di- 
luted with water than otherwise. This fact may be due 
to the oxygen in the water co-operating with the acid in 
chemically decomposing the surface of the steel and con- 
verting the same into rust. 

Steel once rusted is more readily attacked, and its 
decomposition takes place more readily than when in its 
original condition, unless the surface has been divested 
of all metallic oxidation prior to the renewal of the for- 
mation of this compound. 

The tensile strength of rust cannot be relied upon for 
any practical purposes, and it is almost safe to say that 
the amount of steel surface attacked by corrosion has 
not only lost its equivalent amount of strength and is 
burdened by the weight of the rust, but the factor of 
safety is lowered to the basis of the weakest point 
formed by corrosion. 

The formation of rust may be classed as arising from 
two different conditions, which we will assume for the 
purpose of argument are: 

Primary Condition. — Those conditions where the sur- 



face has been expo8e<l to ordinary rust generatinf^ in- 
fluences. Ruch as ordinary atmospheric conditions. 

tiecondary Condition. — Those conditions where the 
surface has been attaclied either by substances atta<hed 
to the surface or Ijy the action of extraordinary atmos- 
pheric conditions. (Atmospheres Impregnated with add 
fumes, &c.) 

Rust can be economically removed very readily by 
mechanical means, and this is the only means by which 
it can be done on a large scale successfully. Abrasion and 
hammering with a tool conveniently handled and ap- 
plied to the surface is the method recommended by the 
author. Flat surfaces that will admit of the use of a 
steel wire brush should be gone over vigorously, both 
lengthwise and crosswise, so that all loose scales and ir- 
regular masses may become detached; then a hammer, 
file and cold chisel should be brought into u.se. as well 
as a painter's wall scraper or putty knife wherever there 
is an accumulation of any thick incrustation. After thij» 
treatment has been completely accomplished, the steel 
brush should again come into play, as before, after 
which a vigorous application of coarse emery cloth or 
sandpaper should be employed, in lieu of which steel 
wool or steel shavings may be substituted for the final 
removal of all loose and scaly formations of rust. 

After the above treatment is completed in as thorough 
a manner as possible, a good heavy bristle brush should 
be used to dust out the finely powdered rust, and then the 
surface should be finally wiped off clean with a dry cloth. 
The hot blast from a painter's torch may sometime^ be 
found to work to good advantage in evaporating as 
much moisture as possible out of the rust, which (jpera- 
tion may result in reducing considerable of it into a 
powdered state. 

The use of the sand blast produces the best results, 
but this is often too expensive a process. 

Any vigorous treatment for the removal of rust may 
be reconmiended in so far that the treatment thus af- 
fected does not crack. l>reak or otherwise injure the 
metal nor leave any condition liable to impair the means 
of protection afterwards to be employed. 

A wet process, or the varioiLS applications of oils, such 
as benzine, gasoline, creosote oil has been recommend- 
ed by many users of the same, and these may be used to 
advantage to penetrate deeply into rust incrustations 

lO 



and thereby aid the hot blast from the painter's torch 
in evaporating moisture, as heretofore mentioned. •I'he 
writer has not, however, found them to possess any 
special beneficial chemical properties in rendering rust 
inactive after the oil had evaporated therefrom. Oil 
once eliminated from rust leaves it in practically the 
same active condition as it would had it not been im- 
pregnated or covered with it. 

The author has found one advantage, however, in 
soaking powdered rust with oils immediately prior to 
its removal, and this is that the rust is capable of ad- 
hering to a cloth when rubbed on the surface thus oiled, 
forming a sort of coagulated mass of rust paste, which 
may be used to great advantage in contributing friction 
or grinding properties, much after the fashion of the 
old style "bath bricks," which were used to clean and 
brighten rough table ware. 

We have observed the reasons why rust forms, and 
we will henceforth turn our attention to the measui^es 
whereby the accumulation of rust may be prevented; in 
other words, the ways and means whereby steel and iron 
may be maintained or kept free from contact with 
oxygen and atmospheric moisture. The ways and means 
by which the same may be done is, of course, to cover 
the surface with a noncorrosive substance; something 
which will not contain nor transmit any oxydizing me- 
dium to the surface of the metal. It must, therefoi-e, a.^ 
far as possible (for all practical and economical reasons), 
possess the qualities of easy application, maximum 
amount of protecting durability and a minimum amount 
of cost. 



Chapter II. 

Some Chemical Elements and Their Symbols. 

By chemical element we mean those substances which 
are not made up of two or more substances. They are 
not necessarily distinguished by any external appear- 
ances, but are known to science as substances which cuu- 
not be decomposed. We can convert them into thousands 
of other substances, but in all cases extra weight and 
material has been added, but none taken from an element 
composing a compound. 

For illustration, we may decompose water by an 
electric current, first weighing the water. The hydrogen 
and oxygen that become separated we know were in com- 
bination, and the weight of both together equal the 
weight of the water, for on combining them again we 
may thus prove that water consists wholly of hydrogen 
and oxygen. 

A nice illustration of the combining of two elements 
may be shown by the burning of finely pulverized metal- 
lic iron in the presence of oxygen. The result of a change 
is a substance which we call oxide of iron. This sub- 
stance obtained has increased in weight, proving that ma- 
terial has been added to it, and not taken from it, the 
extra weight being due to its combination with oxygen. 

This experiment illustrates a most remarkable truth 
in regard to the substance we call iron. By various 
chemical processes we can produce from the metal hun- 
dreds of different substances, but, in all cases, the con- 
dition of the experiment and the relative weight of the 
products prove that material has been added to the iron 
and not taken from it. 

By no chemical process whatever can be obtain from 
iron a substance weighing less than the metal used in its 
production. In a word, we can extract nothing from 
iron but iron ; in like manner we cannot extract anything 
from carbon but carbon, nor, in fact, any material from, 
any element but part of the element itself. 

In chemistry the initial letters of the Latin names 
of elementary substances are represented to denote one 
atom of each element. These are called chemical sym- 



bols. The symbols of these elements, which sometimes 
enter into the composition of paints, oils or varnishes, or 
compounds entering into the destruction of the same 
while under exposure, are as follows : 

Aluminum Al. Manganese Mn. 

Barium Ba. Mercury Hg. 

Calcium Ca. Nitrogen N. 

Carbon C. Oxygen O. 

Chlorine CI. Potassium K. 

Copper Cu. Silicon Si. 

Hydrogen '. . . . H. Sodium Na. 

Iron Fe. Sulphur S. 

Lead Pb. Zinc Zn, 

Magnesium Mg. 

The full list of elements are set forth in almost any 
work on chemistry. Those not here mentioned are omit- 
ted for the reason that they are rarely, if ever, met with 
within the scope of the subject here at hand and would 
only have a tendency to burden the reader with unneces- 
sary and uninteresting complications. 



13 



Chapter III. 

Rust Prevention. 

Since we have noticed that the exidation, rusting or 
corrosion of iron is due to its chemical combination with 
substances with which it has uniting properties, and that 
the resultant product is what we call rust, primarily con- 
sisting of Fe^Os + (HoO), we necessarily conclude that 
we can only prevent the formation of this compound on 
the surface of the metal by maintaining its isolation 
from substances necessary for its propagation, thus reach- 
ing the foundation of its protection. 

There are many ways and means of accomplishing 
this, and iimumerable substances maj^ be used for apply- 
ing on the surface of the metal, all of which have widely 
different characteristics, and also great variation of 
permanency or eificiency ; but we are interested chiefly 
in the most economical and reliable method of doing so. 

We know that water (HoO) and atmospheric oxygen 
alternately acting on the metal surface are the most 
prevalent rust generating mediums, causing rust, and 
therefore should expect to obtain materials for applica- 
tion on the surface of the metal that are not easily af- 
fected by these agents, or the mediums which cause the 
secondary condition to produce rust. 

The efficiency of protective coatings for metal sur- 
faces are entirely dependent upon the character of ex- 
posures, adhesiveness of the coatings, resistance to abra- 
sion, and other qualifications, in consequence of which we 
are led to investigate the various conditions in order 
to meet them in the most economical and convenient 
manner jwssible. 

Oils and greases of various kinds have been used for 
protecting metallic surfaces from the absorption of oxy- 
gen. Great varieties of them are used where the ex- 
posure is not permanent or severe, and the oils or greases 
are to be removed easily after they have served their 
purpose; for example, machinery, firearms, carpenters' 
and mechanics' tools, &c., and even these, if left out in 
the rain, will become rusted soon after atmospheric 
conditions or water obtains the mastery over the coat- 

14 



evaporation or decomposition. The question, however, of 
ing, causing its washing off by friction or elimination by 
temporary prevention of rust by the use of oils and 
greases is of small importance compared to the protec- 
tion of costly steel and iron structures and other large 
metal surfaces, and consequently these will engage our 
attention so that the selection of the proper materials for 
the production of protective coatings may be accom- 
plished in the manner most desired. 

Various paints, oils and varnishes may be used, and 
their protective qualities will last as long as they will 
be devoid of water absorbing properties, and maintyin a 
coherent adhesive coating on the surface. 

The author has ascertained by actual tests that there 
e:s:ists a wonderful variation in the aggressiveness of 
v.iric'us pigii-eiits coacting with atmospheric moisture in 
attacking a metal surface, when the oil has dried out, 
leaving the paint porous enough to absorb moisture. It 
will then be seen that a destructive agent finally en- 
sues from the material which was originally intended for 
a protective addition to the oil. 

Very often an oxide paint pigment is mixed with oil 
and used as a protective coating for metal. The oil 
neutralizes temporarily^ the oxidizing properties of the 
pigment in question, but when the dried paint becomes 
porous by the disintregation, excess oxidation, or evapora- 
tion of the oil, the oxide pigment takes up moisture, car- 
ries it to the metal surface and there conducts a process 
of conioint attack in generating rust that would not be 
possible with a carbon pigment used under similar con- 
ditions. 

Porosity of a paint can often be detected by the ap- 
pearance of stains from moisture with which the paint 
becomes saturated, and by cutting into the moistened 
paint with a pocket knife a fair idea may be had as to 
whether a fresh application of paint is necessary to pre- 
vent moisture from gaining admission through the coat 
ing and coming into direct contact with the metallic sur- 
face. 

The porosity of a paint, however, is very rarely taken 
notice of in time to prevent rust, as it often, while in 
this condition, appears to remain a coherent, adhesive 
mass of fair density and resistance to mechanical abra- 
sion. The most noticeable feature which may be easily 
discerned in this respect, however, is that the coating 



has lost its glossy aijpearance, and appears dead or dried 
out, and even in this condition it is not always porous 
enough to admit moisture entirely through the ooati ug. 

The illustration shows what can be done in the 
laboratory to definitely ascertain the amount of porosity 
of any kind of paint or varnish. Owing to a chemical 
phenomenon, any dried coating of paint having been ex- 
posed to the weather any number of years may be by 
the author easily removed from the metal surface intact 
and without injury. The paint thus removed can be ac- 
curately tested for porosity, elasticity and adhesiveness. 







Plate I. 



and the thickness of it may be tested at different points 
with a micrometer or depth gauge. 

A simpler and more satisfactory way of testing or 
ascertaining porosity of a paint film for the ordinary 
person, however, would be to apply the paint on sheets 
of glass, expose the same to the weather for from one to 
five years at a convenient place, so that the sample may 
be taken down and held up to the light at different stages 
of exposure, and thus any ordinary amount of porosity 
can be very readily seen. 

Paints or varnishes intended chiefly for decorative 

l6 



purposes, that will last for 15 years on the inside wood- 
work of a residence, will do well if they last more than 
five years on the outside woodwork of the same resi- 
dence, and would be an exception, indeed, if they would 
last over two years on the tin roof or gutters, thus demon- 
strating the great difference in exposure and consequent 
variation in the decomposition of the paint on different 
portions of a house. 

It remains for us, therefore, to compound paints for 
specific purposes, made of such material that will give 
them the greatest efliciency. Knowing why, where and 
when the different materials necessary for their composi- 
tion may be used to the best advantage, not, however, 
taking for example the various materials used to pre- 
serve or beautify wood, for while one class of paint may 
be suitable to both wood and metal, this condition would 
merely be an incident when atmospheric or other severe 
exposures would prevail. 

In a majority of instances paint dealers througliout 
the country sell most of the paint intended for wood 
surfaces from $1.25 to $1.50 per gallon. Yet, when it 
comes to paint for metal roofs, the prevailing condition 
seems to be that the dealer canot sell a paint for this 
class of work for more than 50 or 75 cents per gallon. 
Why? Because the uninformed possessors of false eco- 
nomical paint principles believe " If the paint on the 
visible exterior of the house, which is expected to look 
pleasing to the eye, cost a certain price, paint that is put 
up on the roof and which is not necessary to look pleas- 
ing to the eye, should not cost half that price." There- 
fore, the price that controls the quality of paint on the 
market for metal roofs which are sold by the dealer are. 
unfortunately, kept down by popular demand. 

Another reason for a vast amount of cheap trasJi on 
the market for metal protection and called paint is the 
fact tha,t the painter or tinner applies a cheap ' quality 
so that his own temporary profits may be thus gained. 
Painters and tinners invariably are asked by their cus- 
tomers for prices "per square" for doing the job (de- 
tails of qualitj^ and materials omitted), and in order to 
secure the work he is tempted to make a price consistent 
with his chances of a successful issue. As a rule the 
tinner does not care much whether the paint he puts on 
wears one or five years. It makes no material difference 
to him. It may present a good appearance for a few 



months after it is applied, and be almost entirely washed 
off in a year or so afterward. 

There are many paints that will wear well for a 
period of from 5 to 10 years on sheet metal exposed to 
the weather, and also on bridges, but the manufacturers 
of these are compelled very often to give a very close bid 
in order to get a contract and are compelled to use <:heap 
material ; in fact, they have often made the statement to 
those who attempt to sell them high grade paint that 
" our customers will not pay us any more for our ma- 
terial with high grade paint than if it were coated with 
the cheapest that could be obtained." 



i8 



Chapter IV. 

Paint Ingredients, tbeir Classifications and Functions. 

Paint ingredients we shall divide into two general 
classes, namely: Liquids and Solids. They consist of 
the following : 

1. Pigments — (dry powdered, insoluble substances). 

2. Vehicles — (Liquid materials for carrying the pig- 
ments). 

3. Volatile oils and dryers — (Evaporating oils, &c.). 

4. Soluble Solids — (Solid substances for dissolving 
into the liquids . 

Pigments (for paints) are those dry powdered sub- 
stances intended for mixing with liquids for the purpose 
of making liquid or paste paints. 

All pigments when dry hold water freely. 

The pigments used in metal preserving paints are all 
derivatives of minerals, on account of their cheapness 
in price, stability and durability, w^hile those pigments 
which are made of vegetable and animal products are 
used for artistic and beautifying purposes. 

Pigments are generally termed " dry colors," but this 
term is erroneous, for the reason that many pigments do 
not possess any color, being merely white or black. They 
are likewise termed " dry paints " which term is am- 
biguous, for the reason that dry paint is often the sub- 
stance which results in a liquid paint becoming dry on 
a surface. 

The definition of the word pigment, as above stated, 
in order to avoid confusion, should be well kept in mind. 
Pigments we separate into two classes : — Natural pig- 
ments and chemically produced pigments. 

Those which are used in the manufacture of pro- 
tective coatings are, as follows: 

Black pigments. White pigments. i Yellow, red and brown 



Graphite, C White lead, 2PbC0!„ \ Yellow ochre, FegHOs 

PbHoOo. 1 

Lamp black, C. . Oxide of zinc, ZnO. . . .[ Umber, FeaHOe+MnHO* 

Zinc white, ZnO | Iron oxide, Fe203. 

Lead sulphate, PbSOi-i Venetian red, Fe203+ 
j impurities. 

Whiting, CaCOs Red oxide, FesOa + im- 

I purities. 

Barytes, BaSOi Red lead, PbgO^. 

Barium sulphate, BaSO Metallic red, FegOo + 
I impurities. " 

19 



While there are many more pigments used than 
these mentioned for metal preserving paints, the balance 
of them are generally used for their coloring properties, 
or as a means of deceiving purchasers by false state- 
ments, as to extraordinary merits, which they are pre- 
sumed to possess. 

The function of a pigment is to thicken the vehicle, 
to make it opaque with a suitable material or color, to 
give the paint a viscid body (viscosity) and add tough- 
ness and durability to the paints when dry. Some pig- 
ments accomplish this with a great variety of results, 
especially when more or less of it is used than the 
amount necessary to perform its maximum amount of 
usefulness. The exact amount of pigment or pigments 
to be used in making a paint to possess the proper thick- 
ness when spread on a surface to obtain the greatest ef- 
ficiency in its protection can only be ascertained by ac- 
tual tests for their proper working qualities under the 
brush, and also withstanding the kind of exposure met 
with. 

Actual tests for the durability of the pigment are 
necessary in determining the quantity of the pigment to 
be used for the reason that there is such a variety of 
grades of pigments on the market, and they possess an 
individuality of certain capacity for absorbing or " tak- 
ing to " the oils used ; that no set rule can be laid down 
for the actual amount to be used necessary to accom- 
plish the best results. 

This is especially true for the reason that one manu- 
facturer's pigment is at variance in texture, freedom 
from impurities and other qualifications, from another's 
which bear the same name. 

Each class of pigments has a different effect upon 
the drying or oxidizing properties of linseed oil : Some of 
these pigments retard the drying properties while others 
hasten the oxidation to a remarkable degree. 

Among those of the latter may be mentioned all of 
the i)igments containing oxygen in their composition. 
Red Lead (PbaO^) especially. The pigments which con- 
tain oxygen prevent the formation of rust, while they 
are in combination with oils, but when the oils either 
evaporate or become excessively oxidized so that the 
pigments protrude through the film of oil on the dried 
painted surface, or in fact loses so much of the oil 
through exposure that the paint has become porous, it 



then co-acts with moisture and atmospheric oxygen and 
the metal surface beneath the paint becomes rapidly and 
vigorously attacked, whereupon the very pigment which 
was originally a protective medium becomes a rust pro- 
ducer. 

The carbon pigments are elements and consequently 
can only consist of carbon excepting where there is an 
impurity or an adulteration present and this is not as 
a rule premeditated, but rather accidental, at all events 
they are not generally found to any such a degree as 
they are in the lead or chemically produced pigments 
and even when not so the impurities in the former are 
invariably inert substances and do not promote chemical 
activity in producing rust. 

The carbon pigments show a far superior resistance 
to the accumulation of rust, when the oils begin to wear 
out or become eliminated from a painted surface after 
prolonged exposure than do the oxygen pigments, more- 
over they are not affected to any extent by acids whether 
in the liquid or gaseous form. Hence, it will be seen 
that the carbon pigments are to be preferred, graphite 
especially, for graphite which is also used as a lubricant 
possesses such a degree of fineness of texture that it 
gives the paint where it is used as a pigment, such a 
slippery surface when several years dry, that it reduces 
to the minimum the abrasive effect of water, snow, ice or 
mechanical abrasion, etc. 

We may easily destroy the efficiency of the best 
pigment by the use of admixtures whereby the pigment 
or the oil become impaired. A course granular sub- 
stance added to graphite tends to give to the painted 
surface a rougher coating of paint which serves as a 
lodging place for water, which adheres by capillary at- 
traction to the roughened surface. 

Pigments as powdered dry substances are .fixed or 
stable bases, but as coloring materials (excepting the 
carbons) they invariably fade after prolonged exposure, 
and while their stability as a base may be relied upon, 
the various effects which the different pigments possess 
in their co-active properties with drying oils is more or 
less important. It is not so important however, as the 
proper treatment of the oils to be used. 

The most undesirable pigment mixed with the most 
desirable liquid material would make a fairly good paint 
compared to reverse conditions. The complex functions, 



careful preparation of, and extreme sensitiveness of the 
liquids, necessitate a knowledge covering a much wider 
field of experience. 

Moreover, pigments have less latitude in their func- 
tions and present opportunities of physical examination 
for requirements that are easily and finally determined. 

Neither heat nor cold affec-ts pigments to any unde- 
sirable extent, — graphite, Venetian red, red oxide, yellow 
ochre, umber and many others being fire-proof to the 
extent of readily withstanding temperatures, many 
times higher than that necessary to produce a red heat 
on steel. They are also acid proof to the extent of 
not being affected by the most effective acid fumes or 
gases that are possible in open atmospheres. 

Many deceptions on this point are practiced upon 
the public by dishonest manufacturers, who claim or 
infer originality in that they have a fire and acid proof 
pigment, when in fact the majority of the most frequent- 
ly used and cheapest materials for this purpose possess 
these features. 

Deceptions are practiced to such an extent with 
graphite that many interested persons looking forward 
to the purchase of paint containing graphite as a pig- 
ment ask the question. " Where do you get your 
graphite?" 

This deception arises from the fact of various manu- 
facturers, convincing prospective purchasers that they 
own or control graphite mines which produce graphite 
of incomparable purity, or peculiar qualities not possi- 
ble with any other. 

It will be seeii that the question of selecting pig- 
ments that will withstand heat, cold, and acids is a 
simple one, and that the white and colored pigments 
contain oxygen which when combined with a drying oil 
hasten more or less the oxidation of it, and that no risk 
whatever may be run in the selection of inert pigments, 
such as graphite or lampblack in the choice of the best 
and most protective mediums to be mixed with oil for the 
production of the most effective protective coating for 
metal surfaces. 

The liquids used in paints are compound substances. 
They are not fixed or stable, and they constitute ve- 
hicles susceptible to decomposition, vitally affecting the 
durability of the film of a protective coating and therein 
lies room for constant investigation and improvement. 



Vehicles are those liquids which are used with pig- 
ments to carry them in a fluid form for convenient ap- 
plication on the surface for which it is intended. 

The functions which vehicles should perform in pro- 
tective coatings for metal should be that they should 
have a close aflinity with the pigments with which they 
are mixed and form a dry, waterproof and durable non- 
porous coating, one that will not chemically deteriorate 
the metallic surface on which it is applied. Certain oils 
have been found to possess the greater amount of these 
functions and those oils which dry on a surface by co- 
agulation due to oxidation are being used for the pur- 
pose. 

The oils which dry or coagulate by oxidation are 
not numerous, but their extraction, purification and sub- 
sequent treatment are very important, demanding a 
large amount oT technical skill : these oils are more or 
less viscous varying considerably with the process and 
care taken in their preparation. 

The value of an oil for use as a vehicle depends al- 
most entirely upon its durability when dry : thus oils may 
be divided into two classes, the fatty oils, and the vola- 
tile oils, or evaporating oils. 

The fatty oils are greasy and are incompatible with 
water ; when oil and water come together they do not 
mix. (excepting when mixed with strong acids or al- 
kalies) water running over a fatty substance does not 
wet its surface. This property is therefore useful for 
oil paints, for surfaces coated with an oil paint made of 
fatty oil and pigment are protected from the destructive 
action of water. 

Those fatty oils which when exposed to the at- 
mosphere, after being spread on a surface, become solid 
and coagulate into a varnish like coating, are known as 
drying oils and are distinguishible from the non-drying 
oils in that 'the latter remains either fluid or greasy for 
an indefinite period. 

Among the drying oils the best known and most 
commonly used are linseed oil, poppy oil and Chinese 
wood oil. Poppy oil and Chinese wood oil, however, 
are not only too expensive to use for the manufacture 
of protective paints, but they do not possess sufficient 
durability over linseed oil to warrant the excess cost 
necessary for their use. All other drying oils either 

23 



dry so slowly or imperfectly that they are undesirable 
compared to linseed oil. 

The drying power of oils is directly proportional to 
the amount of oxygen they are capable of absorbing, and 
if the absortion of oxygen is not checked the oil becomes 
over oxidized and loses its tenacity and cohesiveness. 

The increase of drying properties of linseed oil is 
accomplished by extracting impurities which chiefly con- 
sist of cellular tissue and albuminous matter, etc. It is 
usually done by storing the oil in large tanks allowing 
the impurities to settle to the bottom after which the oil 
is drawn off, leaving the sediment behind. The oil is 
then clarified by passing through a filter press. 

To further increase the drying properties of linseed 
oil it is boiled in the presence of manganese dioxide, 
manganese borate, red lead, litharge or other substances 
and raised to a temperature high enough and main- 
tained long enough to impart the proper requirements 
to it. The treatment of linseed oil requires such a great 
amount of skill and experience, and the various forms of 
treating the same are so many that the study of it for 
a lifetime would develop new experiences continuously. 
Therefore, the treatment of linseed oil will not be dis- 
cussed at length here. 

When linseed oil dries i't is called "Linoxyn" (Lin- 
seed oil + Oxygen) for the reason that it forms a perfect 
chemical union with oxygen and is then converted into 
the solid material thus named. 

Linseed oil expands during the period of absorbing 
oxygen until it becomes thoroughly dry, after which the 
swelling up very gradually subsides. The expansion 
takes place to such a great extent that it is not only 
readily perceptable by appearance, but a difference in 
weight can be easily ascertained owing to the very large 
proportion of oxygen consumed in the process. 

Almost any one familiar with linseed oil knows that 
after the drippings from a linseed oil can falls onto a 
piece of glass or other non-porous surface, it begins to 
thicken as it dries. 

The formation of a paint or oil skin on the top of 
liquid linseed oil paint exposed to the atmosphere is thus 
easily accounted for as being a formation of linoxyn. It 
will be noticed furthermore that a linseed oil paint skin 
becomes crinkled on the top, and this is due to the ab- 
sorption of more oxygen on the surface where contact 

24 



is had with atmospheric oxygen, than can be ad- 
mitted farther below the surface thereby causing ex- 
pansion on the top greater than the wet side of the skin 
which lies underneath. Gradually the paint skin admits 
more oxygen until the linoxyn gets thick enough to re- 
tard the progress of absorption, and reaches a point 
where it seems to cease. 

It will be seen that pigments mixed with linseed oil 
cut down the percentage of linseed oil in proportion to 
its bulk, for the formation of linoxyn, and the subsequent 
clogging of the pores in the linoxyn by the pigment 
(which, if graphite, does it to a greater degree than the 
coarser pigments) renders the linoxyn for a limited time 
less porous than if the oil were not combined with the 
pigment; provided, however, that not more pigment be 
used than the oil will properly envelop and carry with 
it. 

It will be noticed, moreover, that a fresh dried lin- 
seed oil paint film (without a volatile oil admixture) is 
thicker than when the coating was in the wet state. This 
causes the oil to expand and protrude above the pigment, 
thus exposing the protruding oil to direct attack of dis- 
intregatiug influences, while protecting the pigment at 
the same time. Shortly after the linseed oil becomes 
dry and reaches its fullest extent of expansion it begins 
to subside and to lose its gloss, on account of becoming 
porous, and also for the fact that it becomes excessively 
oxidized and worn down to the pigment; at this stage 
oxidation and disintegration of the vehicle is retarded or 
accelerated according to the nature of the pigment, which 
if carbon accomplishes the former, and if oxygen pig- 
ments the latter. Hence, it will be seen that the organic 
tnatter of a paint which is the vehicle, is the unstable 
and highly sensitive portion of it that requires the most 
important and careful treatment. 

The volatile oils used in paints are those generally 
called terpenes in chemistry. They usually belong to 
one of the groups of hydrocarbons having the same or a 
similar composition as turpentine (CioHie), they are 
highly inflammable and when dropped upon a sheet of 
glass and exposed to the atmosphere for a short time 
completely evaporate. The function of a volatile oil in 
paint is either to adulterate the linseed oil, lessen the 
viscosity of the paint, cause the paint to flow more freely 
so that a thin and consequently quick drying paint will 

25 



ensue, or for the purpose of dissolving gum resins so as 
to make a quick drying varnish, sometimes used as, (and 
erroneously called) a dryer. In this case the volatile 
oil evaporates from the resin leaving a thin coating or 
deposit of the resin of the same character practically as 
it was before being dissolved into the volatile oil. 

The volatile oils usually employed are benzine, petro- 
leum naphtha, coal tar naphtha ( sometimes called creosote 
oil), benzole and turpentine. When these are used to 
any extent in linseed oil, paint not having a solid com- 
position in solution with the oil, the paint loses consider- 
able of its value. The pigment will separate from the 
oil freely and precipitate to the bottom soon after being 
mixed with the oil, the viscosity and adhesiveness of the 
paint would be impaired, the coating would be too thin 
to give ample protection and porosity would result imme- 
diately after the evaporation of the volatile oil from the 
painted surface, thus defeating the very object of a pro- 
tective coating and rendering the coagulated mass of 
dried paint less efficient and durable. 

Metal surfaces defy the absorption of paint to such a 
degree that the admixture of a thin or volatile oil for the 
purpose of creating a penetrating paint is useless. Hence, 
the lack of necessity of using a thin priming coat, which, 
if used, would run down in streaks on a vertical or in- 
clined surface. 

On the other hand, should the paint be made quite 
thick by the use of the pigment it will be done at the 
expense of the vehicle and its adhesiveness, as there will 
not be sufficient vehicle to carry the pigment over the 
surface to be painted, and leave a glossy oily finish. 

Protective coatings for metal should be heavy bodied 
by the use of a heavy bodied vehicle and should be sticky 
enough in the liquid state to take to the metal freely 
from the brush. It should be capable of being brushed 
out thin or flowed on thick before it has time to set and 
should not run on a vertical surface when thus applied. 

It should be quick setting but slow drying ; the former 
to withstand unexpected rain storms shortly after appli- 
cation, and the latter to prevent premature hardening to 
a state of brittleness, not consistant with sufficient ex- 
pansion and contraction of the metallic surface due to 
extreme changes of temperature, which on a dry paint 
film averaging one two hundredth of an inch in thickness, 
would not be inconsiderable. 

26 



Soluble solids, as their name implies, are those solid 
materials which, when melted into a liquid state, are 
capable of being dissolved into the oils for the purpose of 
creating a compound vehicle or a varnish. 

Varnish gums are soluble solids and so are tars, 
pitches, asphaltums and also prepared compositions made 
for the purpose; all of which have various and diverse 
qualifications for use in paints and varnishes for specific 
purposes, and a knowledge of their characteristics are 
necessary in order to select the proper ones for their ade- 
quate use. 

The functions of soluble solids, in protective linseed 
oil paints, are to impart to the oil quick setting, adhesive 
elastic properties, viscosity and durability by way of 
protecting the linoxyn from over oxidation, and that 
state which is commonly called the " chalking off " condi- 
tion of the pigment in the dry paint in which state it 
reaches the point where it has ceased to be a protective 
coating. The prolongation of the protective qualities of 
an oil by the use of a soluble solid depends entirely upon 
the character of exposure, together with the proper 
amount of, and character of, the soluble solid to be used 
in the oil, and also the quality of the oil to be used. The 
boiling down of linseed oil to a thick sticky consistency 
does not take the place of the proper sort of soluble 
solid, for the reason that it will not " take to " a suf- 
ficient quantity of pigment, neither will it allow of the 
production of free and easy spreading qualities. Further- 
more, the oil thus treated does not delay excess oxidation, 
which is the feature most desired. 

The progress of oxidation of linseed oil paints, not 
having a soluble solid, may easily be noticed after fre- 
quent rain-storms, dews or other forms of moisture have 
become evaporated soon after contact with the dried 
paint (similar to the action necessary to rapidly produce 
rust.) 

The paint loses its gloss, becomes dried out eventu- 
ally ; so that the only perceptible part of the paint which 
is left is the pigment. All of these characteristics develop 
to a degree, proportionate to the frequency with which 
the applications of moisture on the surface and its com- 
plete evaporation therefrom has been accomplished. 

A soluble solid to counteract these defects should be 
insoluble in water, but soluble in linseed oil, it should 
be solid yet elastic in its basic state and maintain this 

27 



condition without perceptible change; withstanding ar^ 
large a variation of temperature as possible, it should 
not absorb oxygen nor become perceptibly effected by it, 
and when dissolved into the oil should form a compound 
vehicle which will effectively combat the attack of water, 
heat, cold, oxygen, sulphurated hydrogen gas, carbon- 
dioxide gas, and to a great extent the effects of the 
oxide pigments when the same, of necessity, have to 
be used. It should not impair the proper drying quali- 
fications of the oil; that is not allow the coating to re- 
main tacky or sticky for a long time after it is applied, 
and when necessity requires it, it should allow of suf- 
ficieul volatile oil in combination to allow the paint to 
spread freely and set tough enough in a few hours to 
withstand the deleterious effect of unexpected rainfalls, 
and possess an amount of cohesiveness that the viscous 
mass of solid soluble material will flow together while 
the evaporation of the volatile oil takes place, leaving the 
surface tough, elastic, smooth and waterproof, thus elim- 
inating the defects possessed by all of the straight oil 
paints where volatile oils are used. 

The proper use of a soluble solid in linseed oil paints 
intended to prolong the life of a protective coating for 
metal has heretofore been but very feebly attempted by 
paint manufacturers. Rosin and some of the black 
pitches are often used, and these are used mostly as 
adulterants, or to add a temporary glossy appearance at 
the expense of the durability of the paint which con- 
tains it. 

There has been little or no demand for the use of 
soluble solids in the composition of oil paints for the 
reason that the public has not known the benefits to be 
derived from the use of it. The extra cost necessary for 
its addition to paint, together with the difficulty of ob- 
taining one possessing the requisite physical and chemi- 
cal requirements which can only be ascertained after 
exhaustive and tedious tests covering years of experi- 
menting, have induced manufacturers of protective coat- 
ings to abandon this feature in the composition of their 
products, and as a result almost all of the protective 
coatings now on the market with any claims to being 
high grade are straight oil paints with the omission of 
a soluble solid in their composition. 

Those paints which are not of recognized standard as 

28 



being high grade often have rosin, pitch or a cheap rosin 
dryer in their composition. 

The writer has been confronted with these facts for 
manj- years, and after an exhaustive system of experi- 
ments has succeeded in converting by a chemical phe- 
nomena in the use of chlorine gas, an oil of vegetable 
origin which has no drying or oxidizing properties, into 
a solid rubber-like mass of a light yellow color, complete- 
ly converting the vegetable grease or fatty matter into 
a new substance, which, when melted (necessitating a 
heat of 600 degrees F.) turns black, flows like oil and 
is perfectly soluble in boiling linseed oil, becoming part 
of the vehicle itself and incapable of mechanical separa- 
tion therefrom. 

This soluble solid composition has in the past five 
years proven to be the missing link needed to produce 
a protective coating of the highest efficiency in every re- 
spect, and it is with pleasure to the Avrlter that a pro- 
tective coating with over twice the durability of anything 
yet produced for a top coat, of the highest efficiency is 
now produced and offered to those who are interested 
enough in this subject to demand it for their use. 

The writer has become acquainted with paints that 
were represented to contain rubber (caoutchouc) and has 
personally made paints with this material. Manufactur- 
ers of so called " rubber paints " claim that the rubber 
contained in their paints make the paints more adhesive 
and elastic, thereby extending the life of the paint, by 
reason of its lessened liabilitj' to become hard and brittle 
and eventually crack. 

The extreme high price of rubber, notwithstanding 
the small amount needed on account of its property of 
swelling up considerably in the oils into which it may 
become dissolved, makes its use in paint prohibitory, fur- 
thermore as a paint material it is worthless. 

The author, as well as all manufacturers of rubber 
goods, know that oxidizing oils, or oils used in the manu- 
facture of paint, will rot the rubber shortly after ex- 
posure to the weather, and when it has become dry on a 
surface its shrinkage opens up large crevices and the 
balance of it becomes crumbly, resembling a condition of 
dry rot. These circumstances clearly demonstrate that 
rubber has absolutely no value in paint and that the use 
of it in this respect not only entails a useless expendi- 
ture of money incidental to its cost, but also the cost of 

29 



applying a paint containing materials which tend to cur- 
tail its efficiency. 

In all cases investigated, however, the manufacturers' 
claim to using rubber, either new or old, in pain^'' has 
proven to be a deception in order to obtain a high price 
for a coal tar product, or one no more costly in its pro- 
duction than one of tliis sort. 

We have noted in the foregoing pages the functions 
of pigments, vehicles and volatile oils, and it will be ob- 
served that their action, while in combination as a pro- 
tective coating, is more or less definitely understood. 
Not so, however, with suitable soluble solids, for as 
stated, none but deleterious hard brittle rosins, tars or 
pitches (or if they are not hard and brittle to start with 
they soon get that way under exposure) have been used 
and the author has no hesitancy in saying that he who 
solves the problem of intelligently compounding a solu- 
ble solid composition that will definitely double the life 
of linseed oil as a vehicle in protective coatings without 
increasing its cost, unlocks some of the secrets of chem- 
istry, which, without doubt, is an acquisition of no slight 
value. 



.V» 



Chapter V. 

VARNISHES. 

Their Bases and Cbaracterlstics. 

The line of demarkation as to what constitutes a var- 
nish for a paint has been more or less confused where the 
varnish is not transparent and where the paint has a 
varnish vehicle. In order to avoid confusion we shall de- 
fine a varnish as a liquid substance, not containing a 
pigment, which is capable of drying on a surface over 
which it has been diffused to beautify or protect the 
same. 

A varnish may consist of a drying oil, a drying oil 
with a soluble solid base, or a volatile oil with a soluble 
solid base or the combination of any or all of these into 
one. 

The drying oils we have mentioned on page 23. some 
of the soluble solid bases for varnishes are those men- 
tioned on page 27, and the volatile oils used are those 
mentioned on page 26. 

Varnishes may be either transparent or opaque, and. 
when the latter, they are generally black, such as tar 
varnish or asphaltum varnish, &c. The transparent var- 
nish bases consist of common rosin, which is the residue 
left in the stills after the distillation of turpentine, or 
resins, originating by their exudation from various spe- 
cies of trees, some of which have disappeared centuries 
ago, leaving the resins embedded in the soil, and include 
mastic dammar, Sandarac, copal, kauri, and many others, 
all of which contain carbon, hydrogen and oxygen, and 
are very brittle at ordinary atmospheric temperatures 
and melt at temperatures ranging from 200 to 500 degrees 
F. 

When they are combined with linseed oil or linseed 
oil paints they impart considerable viscosity and adhe- 
siveness to the paint while in the liquid state, and when 
the paint becomes dry higher gloss and better finish, but 
after prolonged exposure to the atmosphere on a large 
metal surface subjected to considerable heat from the 
sun's rays, where rapid radiation of the heat and sudden 
cooling off of the metal causes considerable conti-action 

31 



and expansion to take place; the paint rapidly becomes 
badly cracked and loses its adhesiveness. 

The increased viscosity and adhesiveness of the liquid 
paint is not only lost in the dried paint, but it rapidly 
becomes very hard and brittle. This brittleness is due 
to the evaporation of the volatile matter in the paint or 
the excess oxidation of linseed oil in which a brittle solu- 
ble substance has very little lasting effect. 

Pigments in combination with a resin or pitch tend to 
excessively harden them when they have become dry, and 
thus it will be seen that the separation of a pigment from 
a resin or pitch varnish is an advantage where great 
variations of temperatures are to be met with. 

The pitches which are used in many of the so-called 
protective coating are coal tar pitch, asphaltum pitch and 
petroleum pitch, &c., and these go under so many differ- 
ent names, in order to hide their indentity from pur- 
chasers that it would be impossible to keep track of the 
new names, which are invented to deceive the unwary. 

These pitches have to be made into very hard brittle 
substances by cooking them in kettles before adding the 
oils, otherwise their foundation as a base would not be 
solid enough to allow the substance to harden on a sur- 
face and become dry. 

When pigments are added to a soft pitch with a view 
to causing them to dry it not only augments the lack of 
toughness, but serves to detract the stickiness from the 
pitch, for the reason that pigment alone has no viscosity, 
being a dry substance. Therefore when pitches are to be 
used they should be used in varnishes only, if they are to 
impart their full value to a coating intended for protect- 
ive purposes. 

The melting point of a pitch or resin is the degree of 
temperature necessary to maintain it in a molten state, 
and the brittle point is the degree of temperature neces- 
sary to cause it to harden into a brittle state, which 
state can be noted by striking it with a hammer. 

Almost all of the different pitches have a different 
melting point, and one that softens while in combination 
with paint materials during exposure to atmospheric 
temperatures, and will correspondingly harden to a state 
of brittleness when the temperature lowers is sure to 
crawl and crack on the surface. These cracks form in 
transverse directions, forming a defective surface, which 
is known as being " alligatored," resembling in shape the 

32 



peculiar formations on the surface of an alligator skin. 

When an " alligatored " surface forms and continued 
contraction and expansion of the metal ensues the edges 
of the alligatored scales will finally curl up, " letting go " 
of the metal entirely, thus allowing moisture and dust to 
get underneath them, facilitating the process of ridding 
the surface of the paint and promoting active rust forma- 
tions. 

The melting point of a pitch or resin may easily be 
ascertained by placing the same in a small iron cup, into 
which the bulb of a thermometer has been inserted, and 
noting the results after heat has been applied to the 
bottom of the cup. 

Most of us know, however, that atmospheric heat on 
a warm day will soften coal tar pitch to such an extent 
that it will run on a surface or may be pulled out into 
long strings and after cooling it by dipping it into a basin 
of cold water it will fly into small pieces or may be 
finely pulverized by a simple blow from a hammer. This 
once soft and afterward brittle condition will be noticed 
where paints or varnishes containing these pitches are 
exposed on a surface at atmospheric temperatures, pro- 
vided, however, that the same has been applied on the 
surface heavy enough to obtain from them their maxi- 
mum amount of wear. 

In proportion to its bulk it requires a large amount 
of volatile oil to reduce a resin, tar or pitch to a liquid 
condition thin enough to be capable of proper spreading 
properties, with a paint brush, at a temperature of 60 
degrees F. Hence a very thin deposit of the solid base 
of the mixture will be left upon the surface after the 
volatile oil has evaporated. If extreme care is not taken 
In brushing it on thick enough to allow for the evapora- 
tion of the volatile oil and leave a substantial coating, 
lack of durability will be inevitable, for the coating 
which will remain on the surface will be so thin or 
badly disintegrated by the solvent action of the oil first, 
and its evaporation afterwards, that its adhesion to the 
surface will be a matter of only a few months, or even 
weeks, when subjected to atmospheric exposure, and 
soon afterwards no trace of it is liable to be seen what- 
ever. On the other hand, should it be spread on too 
thick, a badly alligatored surface will result. These are 
the reasons why tar and asphaltum varnishes are so un- 
reliable on tin roofs, and the author knows of no way 

33 



iu which they may be made reliable in a practicable way 
so that any one who knows how to spread paint can have 
some sort of definite assurance that it is going to last 
two years at least. For, as explained, the thickness of 
the coating has considerable to do with it. and as the 
volatile oil evaporates so quickly, and indefinately in 
varying temperatures, lack of uniformity of the deposit 
left upon the surface is sure to ensue. In fact, the author 
knows of hundreds of instances where a tar varnish 
applied to a tin roof Avould lasjt four years, and be alli- 
gatored, and part of the same varnish taken from the 
same barrel and applied by the same painter the follow- 
ing day on an adjoining roof of the same conditions of 
surface would dry out and wash off within a year. More- 
over, weather conditions and temperatures render the 
prevention of these defects of a highly volatile varnish 
impossible. 

Rosin more readily impairs the stability of a coating 
into which it has entered than any of the other resins, 
and every ounce of it combined with a gallon of paint 
can be noticed to detract from its wearing qualities. 

Many of the so-called paint dryers on the market are 
nothing more or less than a thin rosin varnish, and in 
consequence should be avoided. If, however, a dryer is 
absolutely needed, only oil dryers with thickening or 
oxygen absorbing properties should be used, and then 
only in minimum quantities, necessary to meet unavoid- 
able requirements. 



34 



Chapter VI. 

I>lag]iosiii<^ Conditions of Expoft>iire. 

This is an important matter in the selection of the 
most suitable paint for a pm-pose. 

Plate II shows a smokestack below the roof in a sheet 




mill. The paint was made by one of the most reputable 
manufacturers in the country, and was compounded of 

35 



high-grade raw materials. The manufacturer guaranteed 
it to last one year on this stack, which did not get over 
700 degrees F. The condition of the paint, as shown in 
the illustration, became so one week after it was applied 
and thoroughly di'y. Paint taken from the same mix in 
the barrel was applied on a tin roof in the neighborhood 
the same day, and five years afterward was in perfect 
condition, thus illustrating the proper use for that par- 
ticular kind of paint. On the other hand, a cheaper and 
differently made paint was applied to this stack a few 
days later, after the scales were cleaned off, and it stood 
the exposure fairly well for one year, and on a tin roof 
in the neighborhood it did not preserve the metal over 
four months. 

Samples, which are occasionally painted on small 
pieces of tin and sent out by the manufacturers to bend 
and twist, appear all right until they have been exposed 
to the weather for a year or so at which time their beau- 
tiful appearance and preserving qualities have quite van- 
ished. 

In order to select a protective coating to the best pos- 
sible advantage the conditions of exposure should be thor- 
oughly understood first ; other conditions, such as the 
character of the surface, and number of coats to apply 
should follow. 

The exposure of dry paint surfaces may be conveni- 
ently divided into eight classes as follows: 

1. Ordinary interior exposures. 

2. Ordinary exterior exposures. 

3. Extraordinary interior exposures. 

4. Extraordinary exterior exposures. 

5. Extraordinary exposure to heat (other than atmos- 
pheric). 

6. Extraordinary exposure to cold (other than atmos- 
pheric). 

7. Extraordinary exposure to liquids (other than at- 
mospheric) . 

8. Extraordinary exposure to abrasion (other than at- 
mospheric). 

No. 1. Ordinary interior exposure rarely covers a va- 
riation of temperature of more than 60 degi*ees F.. conse- 
quently the expansion and contraction of the surface met 
with in this class of exposure is so small that it has very 
little effect upon an ordinary paint properly put on and 
of good materials, neitlier does moisture and its rapid 

36 



evaporation prevail, so that here we have a condition 
notable for its simplicity. Take, for instance, several 
small sheets of tin or iron with clean, bright, dry sur- 
face, coat them with coal tar varnish, asphaltum var- 
nish, or, in fact, any cheap paint, and when thoroughly 
dry lay them aside in the drawer of a writing desk ; 20 
years Jater they will be in as good condition as the day 
they were stored away. The sheets of metal, even with- 
out paint, laid away, in like manner for the same length 
of time, will also be found to be in excellent condition. 
Structural iron work imbedded in cement or concrete or 
otherwise incased should have one coat of paint applied 
at the shop and two coats afterward, for the reason that 
subsequent coats cannot be applied after the building is 
completed, and once painted it is expected to remain so 
as long as the building lasts. Cement and concrete, more- 
over, are more or less porous and draw dampness to the 
metal. 

No. 2. Ordinary exterior exposure meets with climatic 
conditions varying over 125 degrees F., ranging from the 
chilly blasts of cold weather to the scorching rays of the 
sun. Here expansion and contraction holds full sway, 
tugging and straining at the adhesive and elastic prop- 
erties of the paint while adhering to a surface not suc- 
ceptible to paint absorption. 

Hail, snow and ice, thawing and freezing, rain and its 
evaporation attack vigorously the organic properties of 
the vehicle in a paint. When a varnish is used to with- 
stand this class of exposure the heat from the sun con- 
tinues to liberate what volatile matter it contains until 
it becomes baked so hard and brittle that its adhesive- 
ness subsequently becomes a matter of only " here and 
there." If the varnish is a thick coating it is sure to be- 
come alligatored when the metal expands and contracts 
while in the hard condition, and if it is a thin coating 
it will become reduced to powder and wash off. This 
sort of exposure requires a paint of superior, elastic, ad- 
hesive, oxygen and water resisting properties, and as the 
top coat is the one subject the most of all to these condi- 
tions it should of necessity be made of carefully treated 
linseed oil, graphite and a suitable soluble solid composi- 
tion to protect the oil so as to add permanence to the 
vehicle as explained. The reason for using graphite for 
the pigment is explained on page 22. 

The class of steel work generally coming under this 

37 



class of exposure is bridges, ornamental ironwork, fences, 
fire escapes, gutters, valleys, spouting, roofing, siding, 
towers, sheathing and shutters, &c. New materials of this 
class should receive at least one coat of paint at the works 
and one coat after it is put up. 

No. 3. Extraordinary interior exposure, such as will 
be met in damp cellars, livery stable roofs (exposed on 
the under side to ammonia fumes), cast house roofs at 
furnace and foundries subjected to steam and heat, under 
side of roofs of steel mills directly over sulphuric acid, 
pickling vats, pulp mills, paper mills and ships* holds 
which sweat continuously, &c., have considerable effect 
upon the paint on the surface and paint thus exposed 
should dry harder and have more soluble solid in its com- 
position than class No. 2 : two good coats of the most 
suitable paint for this class of work are in most cases 
most satisfactory, and when the top coat loses its effi- 
ciency it should be replaced with another one before ac- 
cess to the metal is gained, as this will save considerable 
labor in removing rust which would otherwise form. 

No. 4. Extraordinary exterior exposure are those ex- 
posures where the atmosphere is surcharged with acid 
fumes, which generally emanate from open coke ovens, 
chimneys, locomotive stacks and chemical works. &c. The 
effects of this class of exposure varies extensively, a 
great deal depending on the distance from where the 
fumes emanate and the character of them. Painted metal 
work of all kinds, especially roofs and bridges, in the 
vicinity of these quickly lose their protective coating if 
the paint is not made of the proper materials to with- 
stand the exposure. Like class No. 2, this exposure 
necessitates the use of a protective coating capable of 
withstanding considerable expansion and contraction, and 
should not harden so much as the paint needed for class 
No. 3. It must furthermore have a vehicle protected by a 
soluble solid composition properly prepared to stand the 
surcharged atmosphere : and an inert pigment, such as 
graphite, white lead and red lead pigments, especially are 
to be avoided in this class. If this form of exposure is 
very severe three coats of paint should be used on the 
metal work. 

No. 5. Extraordinary exposure to heat takes in those 
conditions where heat is produced by artificial means 
greater than atmospheric heat, and comes into direct 
coni:act with the painted surface. This heat may come 

38 



in contact with paint exposed to outside atmosplieres, or 
it may come in contact with paint exposed to inside at- 
mospheres. The class of materials subject to the former 
consists of smokestacks, blast furnace stoves and locomo- 
tive front ends, &c., and those subject to the latter con- 
sists of boiler fronts, furnace fronts and hot air and 
steam pipes. In all cases coming under this class the 
maximum amount of temperature should be ascertained. 




Plate III. 

and if found to be more than the boiling point of water 
(212 degrees F.) a compound vehicle will be necessary. 
As explained on page 21, ordinary pigments, such as 
graphite, Venetian red, yellow ochre, or umber, are prac- 
tically fireproof, consequently the fact remains that the 
heat resisting properties of a paint is equal to the amount 
of heat which the vehicle will stand. Should the heat run 

39 



over 600 degrees F. little or no linseed oil should be used, 
and a soluble solid composition of a melting point a few 
degrees higher than the hot surface must necessarily be 
expected to be used for any permanence in this respect. 

In 1902 officials of The American Sheet Steel Com- 
pany called upon the author to make several tests per- 
sonally on the hot smoke stacks over their pair furnaces 
and slab mills, stating that the paint when selected and 
bought would have to be applied to the stacks while hot. 
for the reason that the furnaces were always going and 
the fires could not be put out without too much expense 
and inconvenience. 

Twenty-two different kinds of paints were tested in 
this manner, no two showing similar results. The author 
rather than allow anyone else to prepare the surface 
for the test and not do it thoroughly, did so himself, so 
that the experience thus gained would be of subsequent 
value. Plate III shows the author scraping the hottest 
portion of the stack which was to be tested. This opera- 
tion was followed by the painter. 

Flames were bursting forth from the tops of the 
first, second, third and fifth stacks, and the roofs were 
so hot that the soles of the shoes were scorched, and 
those making the test were compelled to keep moving. 
Vapor can be seen coming from the wet paint on the 
second stack, and the paint brush had to be moved fast 
in order to keep the bristles from burning. The scraping 
tools became so hot from induction that they were 
handled with difficulty. 

Plate IV shows the tools that were available for 
cleaning at the time, and Plate V shows rust scales and 
old paint scales (one-quarter the diameter) removed. 

Red heat of steel or iron is over 900 degrees F. and the 
author knows of no vehicle that will stand this heat and 
be water proof and rust preventing at the same time. 

Whitewash or calcimine, sometimes called water 
paints, and sodium silicate used as a vehicle, will stand 
much more than 900 degrees F., but paints made of these 
will not stand water or moisture, nor will they stick to 
the surface long after being thoroughly hardened. Only 
one coat of paint is recommended by the author for this 
class of work, for the reason that extremely hot sur- 
faces usually burn off the paint prematurely, in which 
case frequent applications are necessary, and two coats 
would be a considerable expense in so doing. It would 

40 



be folly, bowever, to expect to keep paint in a good con- 
dition for more than a few months on a surface as hot 
as 900 degrees F. The nearest material approaching a 
protective coating to stand over 900 degrees F. would t)e 
a coating of porcelain enamel. This would take more heat 
than 2000 degrees F. to melt it on the surface, and for 




this reason it would be an expensive and impractical 
operation, ix>ssible only on new work while in the factory 
preparatory to erection. 

An approximate estimate of temperatures on a metal 
surface maj' 'be had by applying liquids of known boiling 
points on the surface and noting if they 'boil. 

No. 6. Extraordinary exposure to cold generally takes 

41 



ill conditions such as cold storage plants having steel con- 
struction within, the inside surface of steel plates com- 
posing ships bottoms, the outside surface of standpipes 
or water cylinders of hydraulic pumps, &c. The varia- 
tions of temperature on these surfaces are slight or are 
below the amount necessary to injure a paint for the rea- 




%♦♦ 



Plate V. 

son that they rarely if ever reach higher than 70 degrees 
F. The gi-eatest amount of injury which these conditions 
inflict to a paint is due to chilled vapor resulting from 
a damp atmosphere condensing on the surface resembling 
sweat. Should the conditions be such that this sweat 
reappears soon after it has been removed, preventing the 
maintenance of a dry surface long enough to apply the 

42 



paint and enable it to become dry, the painting should he 
deferred nutil the proper condition can be met with and 
then paint that will di-v and harden qnieklv should be 
used. This will necessitate the use of a paint which has 
very little or no oxidizing oil. 

A volatile solvent varnish vehicle paint containing 
graphite for a pigment and a soluble solid known to the 
author as Nicaragua giun. has been found to be the hest 
for this class of work. This kind of paint hardens so 
thoroughly and so quickly that it would not stand such 
exx)Osures as class No. 2 with any degree of certainty 
or satisfaction, and therefore should only be used for ex- 
posures of this class. 

No. 7. Extraordinary exposm-es to liquids takes in a 
class where water is maintained in direct contact with the 
paint, such as ships bottoms, steel intake cribs, tanks, 
standpipes and portions of gas storage tanks commonly 
called gas holders. These require a compound vehicle 
paint with very little oil, or a varnish paint similar to 
that used for class No. 6, but should be heavier bodied 
and contain less volatile solvent, so that a heavy coat- 
ing of the basic material will remain on the surface. 
This is necessary to withstand the extreme aqueous pres- 
sure against the paint film. 

No. S. Extraordinary exposure to abrasion takes in a 
class where friction eliminates a paint from a surface be- 
fore it gets a chance to demonstrate its preserving proper- 
ties by virtue of exposure to atmosphere, heat, gases or 
water, such as coal bunkers, ships' holds, freight cars and 
metallic shields underneath the flooring of bridges under 
which locomotives pass emitting carbonaceous grit from 
the smokestacks. 

This class of paint should be slightly harder than that 
used for exposure No. 2. but not hard enough to become 
cracked or broken by violent hlows, such as that of coal 
being loaded into cars and striking the surface of the 
car. It should have graphite exclusively for a pigment. 
This paint when almost dry should he dusted with the 
best quality of slippery dry graphite, then allowed to 
dry and then polished with a woolen swab or sheep skins 
with the wool on (using the wooly side). The finished 
surface will then have a highly glazed surface that will 
withstand more mechanical abrasion than any other form 
of paint coating which the author knows of. 



43 



Chapter VII. 

The Selection of the Most Suitable Preserratlve. 

The selection of the most suitable material should be 
governed not only by the class of exposure to be met 




Plate VI. 

with, but also the number of coats of paint to be used 
and the time allowed for it to dry properly. 

Plate YI shows two samples selected from several 

44 



hundred of which the author has been giving thorough 
time tests. These samples were exposed in the Pitts- 
burgh District, where the atmosphere is surcharged with 
sulphuretted hydrogen, carbon dioxide and sulphur fumes, 
&c. The paint was applied on bright, smooth sheets of 




steel. No. IV shows an improperly prepared graphite 
paint and No. VII shows a properly prepared graphite 
paint 

One shows that before the end of four years the 
protective qualities of the paint were exhausted and the 
steel to be badly eaten with rust. The other shows that 

45 



^OfL 



the protective qualities of the paint were not impaired 
during the same length of time, the metal remaining as 
bright underneath the coating of paint as the day it was 
applied. 

No. IV was taken from the regular stock paint of " a 
get rich quick " paint concern and was advertised as 
'* their best grade " and the " best paint in the world." 

No. VII was manufactured by a concern who does not 
make bombastic claims for their products, but depend 
upon their reputation for their continuance in business. 

An enormous spreading capacity of a paint is often a 
misleading, fradulent or deceptive proposition offered to 
purchasers of paint in order to secure their patronage. 
The spreading capacity of almost any paint of good body 
may be increased by thinning it considerabh' with a 
volatile or a drying oil, and this decreases the cost per 
gallon by reason of the increased bulk resulting from 
its extension by the use of a cheaper thinning material 
than the cost of the paint. Therefore claims for supe- 
riority of a paint due to its superior spreading capacity 
should not necessarily add anything to the value to a 
statement of this sort. Furthermore, the less spreading 
capacity a paint has the more body it possesses. This 
body is generally the most costly part of a paint, and 
the fact that it is too heavy or thick to possess spreading 
qualities equal to a thinner paint should not detract from 
its value after taking into consideration the cost of the 
thinners necessary to reduce the body and increase the 
quantity and spreading capacity to the extent most de- 
sired. 

A basis whereby deductions may be made to approxi- 
mate the average thickness of a coat of paint on a smooth 
flat surface, which does not absorb any of the paint, may 
be readily calculated in the following manner : 

A legal standard United States gallon we know must 
contain 231 cu. in., and if 1 gal. of paint is spread ovot 
a surface containing 231 sq. ft., the wet paint will average 
1-144 in. thick. 

In like manner should the paint be spread twice as 
far and cover 462 square feet to the gallon it would be 
1-288 in. which thickness can be compared to the thick- 
ness of the leaves of a book having 288 pages to the inch. 
Now when the paint is dry it will either thicken or be- 
come thinner — the former if a linseed oil paint and the 

46 



latter if a volatile oil varnish paint — therefore allow- 
ances should be made accordingly. 

The vrriter believes that a protective coating averag- 
ing less than 1-144 in. thick is not sufficient protection 
to a metal surface exposed to any class of exposure in- 
tended for long service and that 1-72 in. is not necessary 
in any case where high grade material is used. 

The spreading capacity of a paint should be averaged 
when based upon a standard condition of surface the 




1 SQUARE FOOT 
144 SQUARE INCHES 



































































































































































































































































































HS COVERED 
BY 




most suitable for the purpose being bright clean tin 
sheets or glass and estimates for other forms of surfaces 
based upon variations from the standard. The spread- 
ing capacity will also depend upon the temperature and 
for convenience 70 degrees F. is recommended. 

Careful and slovenly spreading of paint will cause 
a great variation and lack uniformity of thickness of a 
coating, nevertheless in any case the attainment of an 
average estimate of thickness can not be depended upon. 
When, however, a paint is advertised to cover 1000 sq. 
ft. to the gallon it means necessarily that the coating 
must average less than 1-576 of an inch thick which may 
be compared to thin tissue paper. 



47 



Pigments may easily be tested for their fineness of 
texture by simply rubbing them in a dry state between 
the fingers or upon the palm of the hand, and if the 
pigment is mixed in a drying oil it can be separated out 
and dried by thinning the paint with gasoline, vigorously 
shaking together the mixture allowing the pigment to 
settle to the bottom, and washing out the heavy oil, then 
pouring off the liquid, repeating the operation until all 
of the drying oils have been extracted, after which the 
pigment may be dumped out upon a sheet of blotting 
paper and allowed to dry. 

It will be noticed that the best grades of graphite 
" rub up " into a higher gloss between the fingers than 
any other known paint pigment and that when this pig- 
ment does not " rub up " into a slippery finish it is 
adulterated. 

Vehicles may be tested in a simple way for com- 
mercial purposes by allowing the pigment to settle to 
the bottom, pom'ing the vehicle upon a piece of glass, al- 
lowing it to dry for 48 hours and then subjecting it to a 
temperature of say 200 degrees F. (up near a hot stove) 
for several hours, after which cool off by soaking it into 
cold water for 30 minutes, wipe dry with a cloth vigor- 
ously and see whether any of it will rub off, after which 
take the blade of a pocket knife and cut into it with a 
long steady cut beneath the paint and along the surface 
of the glass. If the vehicle can be then cut leaving long 
tough and elastic strips it can reasonably be expected 
to possess good qualifications for ordinary exposures met 
with. However for exposures such as 3, 4, 5, 6, 7 and S 
they should in addition be given actual time tests to 
the exact exposures to be met with, keeping detailed ac- 
counts of the conditions and the kind, quality and 
amount of raw materials used, so that the paints thus 
prepared for use may be intelligently compared for future 
selection. 

Driers should be given the same test as the vehicle, 
noting, however, the sti*ength of the drying properties, by 
the amount necessary for use with the vehicle and the 
time consumed in the drying of the oils thus tested. 

A paint oil or varnish is considered by the author 
to be perfectly dry at such time when at a temperature 
of 70 degrees F. it refuses to adhere to a sheet of writ- 
ing paper smoothed over it and pressed down hard by 
the palm of the hand. This condition at the very least 

48 



should prevail before additional coats of paint are ap- 
plied. 

However as much additional time as this condition 
requires to consume should be given before the same is 
attempted. 

Volatile oils may be tested by allowing them to 
evaporate from a sheet of glass and noting whether 
there is a greasy deposit left on the surface, which if so, 
shows a substance which when entering into the liquid 
portion of a paint will seriously prevent the drying of 
it and cause an endless amount of annoyance, sometimes 
necessitating the removal of the paint entirely, which if 
not done would prevent the proper adhesion of more 
coats of paint. 

A great deal more might be stated relative to the 
testing of materials. 

The writer has noticed that the signs of the times 
show an increasing tendency unfortunately on the part 
of the general property owner to leave the question of 
maintenance and selection of materials to others. The 
luxurious modes of entertainment now prevalent entice 
the property-owner to more pleasant occupations during 
the intervals of the rush of business than formerly, when 
each property owner not only painted his own house 
, but made his own paint and made it to last. 



49 



Chapter Vlll. 

Deductions and ConeluMioiis. 

After pursuing the subject of rust prevention it be- 
comes very apparent that many questions are involved 
that do not .clear the way. for those who cannot give it 
much thought or attention. 

It does not take much of either, however, to deduce 
the following facts : 

1. The property owner should be satisfied that the 
surface to be protected is as clean, dry, smooth and firm 
as it is possible to get it before his time, money or pa- 
tience is expended thereon. Without this important con- 
dition any means to be employed would only be wasted. 
Inasmuch as the preparation of the surface, the employ- 
ment of the proper kind of material and the quality of 
work done, when undertaken by a contractor may easily 
be manipulated by him in such a way that he may greatly 
profit financially to the detriment of the owner, it is 
recommended that the owner purchase his own material 
direct and hire his men by the day to do the work. Even 
should the men put in more time than necessary, the 
chances are that the work will not have been slighted, and 
that the total cost of the job would be much less than the 
same quality of work and materials would be supplied by 
the contractor. 

2. The owner should purchase his paint in different 
shades, using a different shade for each coat, so that the 
detection of omissions in thoroughly covering the surface 
may be readily accomplished. The paint should be deliv- 
ered on the ground in sealed packages guaranteed by the 
most responsible maker in whom the purchaser may have 
confidence. 

3. It should be contained in receptacles that will main- 
tain it in a good condition, and enable it to be thor- 
oughly mixed or agitated during the progress of the work, 
so that the paint thus used is of a uniform consistency 
until the work in hand is fully completed. 

Rain, dust, sand, mortar, plaster or refuse from build- 
ings close by have often found its way into the paint 
barrel, rendering the contents unfit for use. 

The great difference in the specific gravity between 

50 



pigment and vehicle causes the former to readily precipi- 
tate to the bottom in 'a very short time, even in the very 
best paints, and the best results can only be obtained by 
energetically^ keeping the paint stirred up. 

The great drawback to the ordinary paint barrel is 
due to the fact that the head must be removed in order 
to thoroughly agitate the contents by means of a board 
or paddle. 

To remove the head without destroying the barrel 




(which cost generally over $1.50 each) two or three hoops 
must be driven up to allow the staves to spread at the 
top, so that the head can be disengaged from the chime. 
When the staves spread in this manner openings are left 
between them, allowing the paint to run out, entailing 
waste and loss of time tightening up the barrel again. 

Barrels containing various kinds of paint mixers 
have frequently been tried, but almost always have 

51 



proven either complete failures, or so unreliable that de 
pendence upon them results invariable in the abandon 
ment of their use. . 

An ordinary ban-el filled with good paint contains sev- 
eral hundred pounds of pigment, which when settled to 
the bottom becomes tough like putty. 

The barrel paint mixers that have been tried beeomea 
imbedded in the pigment and stuck fast with as much 
resistance apparently as would be experienced trying to 
turn a spade around when it is shoved down deeply in 
firm soil. 

These drawbacks have led the writer into experiments 
resulting in the construction of a barrel paint mixer 
which is recommended to do the work. 

The stem and crank as seen in the above illustration 
(lA, 2A, 3A) is made of a one-piece malleable casting, 
and the side arms or paddles are made of stiff spring 
steel Ys in. thick. These side arms are connected by 
means of loosely fitting rivets, and may be drawn up 
edgewise through the pigment so as to fold up, thereby 
reducing the diameter of the agitating surface, so that a 
portion of the pigment may be moved and mixed with the 
vehicle ; after this is done the agitator paddles may be 
spread out as required until the whole width may be used 
for all of the pigment at one operation. 

The mixer should be turned rapidly to the right for 
8 or 10 revolutions, and then reversed quickly, this gen- 
erates an undercurrent coming from the top in the form 
of a whirlpool, and leaves nothing to be desired in the 
matter of thorough agitation. 

It is an important fact that the first coat of paint 
usually applied by the manufacturers on newly made 
metal work is of the cheapest variety, unless specifica- 
tions and contracts to the contrary offset this result. 

Every owner of property containing metal work that 
needs protection should thoroughly understand " what he 
needs as a preservative, and demand that it be properly 
applied by the painter." 

Paint should be spread on a surface in temperatures 
between 50 and 90 degrees F., and should be spread on 
carefully that all air bubbles under the paint should be 
eliminated. 

The application of paint with a machine or spray 
should not be encouraged, for the reason that air bub- 
bles get under the fine spray and prevent the close ad- 

52 



lierence of the paint to the surface, and also has a tend- 
ency to aerate the paint. The first coat on metal should 
not be quite as elastic as the succeeding coats. It should 
dry hard, tough and slightly yielding. Its subsequent 
hardening is somewhat prevented by the coat on top of it. 

The last coat, or top coat, should dry slower than the 
one underneath, so as to withstand the drying tendency 
of the weather and meet expansion and contraction where 
it is mostly needed. 

Black paints are the most opaque and should be used, 
not only because the material out of which they can be 
made affords the production of the best protective coat- 
ing, but also for the reason that it presents a striking con- 
trast to the color of rust or corrosion. 

When red or brown paints are used the appearance 
of rust can only be detected at times when close inspec- 
tion is promoted, and this is very often deferred by over- 
sight or neglect. 

Too much importance cannot be attached to the neces- 
sity of preserving metal before corrosion or oxidation 
has taken place. 

The loss that generally ensues when metal surfaces 
are not continually protected in every corner and crevice 
is rarely appreciated. The wasted metal resulting from 
one moment's chemical action can never be replaced to 
its former condition (commercially speaking), and the 
section so effected is ofttimes so very difficult and costly 
to replace, especially in hidden structural work and 
bridges, that these matters are in many cases postponed 
until the whole structure becomes condemned as dan- 
gerous and a new one needs to be, built 

Care should be employed by the purchaser of new 
structural work, bridges or sheet metal work, where the 
protective coating is furnished by the contractor ; in see- 
ing to the explicit and proper wording of the specificarj/ 
tions so that the right brand, make and best paint ma- 
terials are clearly defined so as to leave no valid chance 
for substitution. This rule should always govern wher- 
ever and whenever good paint is wanted. Specifications 
for applying the paint should always state "the number 
of coats wanted and that there should be no air holes, 
moisture, oil, grease or dirt under the paint; that it 
should be well brushed on by hand to a thoroughly 
cleaned and dry surface, thoroughly cover the said sur- 
face and be applied in dry weather between temperatures 

53 



of 50 to 00 dej?rees F. (unless tlic paint is a special kind 
and is shovvu by the purchaser to especially require dif- 
ferent temperature for application"). 

This should never be left for engineers to do, for a 
wide diversity of opinion exists as to what make or 
brand should be used, even among those of many years' 
experience. 

Furthermore, engineers or architects very often re- 
fuse to specify any particular make of paint, for obvious 
reasons. It savors of partiality and leaves room for se- 
vere criticism. On the other hand, if the contractor can 
evade supplying an established brand of high grade ma- 
terial and suit himself in the furnishing of paint made 
of raw materials selected by himself, rendering it im- 
possible for the engineer (without giving the material a 
daily chemical analysis), to ascertain its true value he 
has the chance to utilize the greater of the two evils to 
his own profit. 

In cases where the engineer will not consult with the 
owner on the brand or make of paint to be used and spec- 
ify the same in the contracts, the author suggests that 
the specifications read as follows : " All paint and paint 
materials used must be selected or approved by the 
owners before the same is permitted to be used. It shall 
be subject to the inspection and refusal of the engineer 
when the same is not branded or recognized as such." 
This would relieve the engineer of a responsibility which 
is not necessary for him to be expected to shoulder. 

No engineer, in designing a structure, can make effi- 
cient allowance for decay, for the reason that the time, 
place and extent of such action is an unknown quantity 
and always will be. 

Loss of life and property due to collapse resulting 

from decay is a serious theme to reflec-t upon. Any ex- 

, isting doubt as to the necessity of giving the work a good 

coat of good paint should be decided upon before it is 

too late. 



54 



XV, °'' <^°NGRESS 



019 408 587 4"^ 




